JPH08125098A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE: To prevent peeling of an external lead terminal from a metallized wiring layer together with a brazing material by connecting the layer of an insulating base to the terminal via gold-tin-lead-silver alloy or gold-tin-lead- palladium alloy. CONSTITUTION: The metallized wiring layer 4 of an insulating base 1 is covered with a gold plating metal layer 8, and an external lead terminal 2 is sequentially covered with a silver or palladium plated metal layer 9 and a tin-lead alloy plated metal layer 10. Then, the inner end of the terminal 2 is placed on the layer 4 of the base 1, heated, gold-tin-lead-silver alloy or gold-tin-lead-palladium allow is formed between the layer 4 and the terminal 2, cooled to be solidified, and the terminal 2 is connected to the layer 4 of the base 2 via the brazing material 6 of gold-tin-lead-silver alloy or gold-tin-lead palladium alloy. Thus, an inner semiconductor element is electrically accurately and effectively connected to an external electric circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device used in an information processing device such as a computer.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device used in an information processing device such as a computer is provided with a semiconductor element, a die pad on which the semiconductor element is mounted, and a plurality of external lead terminals surrounding the die pad and extending at a predetermined interval from the vicinity of the die pad. And a semiconductor chip, a die pad, and a molding resin that covers a part of the external lead terminals, and a lead frame in which the die pad and a large number of external lead terminals are integrally connected via a frame-shaped connecting band is prepared. A semiconductor element is mounted and fixed on the upper surface of the die pad of the lead frame, and then each electrode of the semiconductor element and an external lead terminal are electrically connected through a bonding wire, and the semiconductor element, the die pad and the external lead terminal are also connected. It is manufactured by covering a part of the mold resin with a mold resin.

The lead frame is made of a metal containing copper as a main component, a metal containing iron as a main component, etc., and a conventionally known punching process or etching process is applied to a thin plate made of a metal containing copper as a main component. It is manufactured by applying metal processing such as.

However, in the conventional lead frame formed by punching or etching, the width of the external lead terminals and the distance between the adjacent external lead terminals are 0.3.
Since it is difficult to make the width extremely narrow, such as mm or less, and when a semiconductor element with a large number of electrodes has been mounted in recent years due to high integration, a large number of external lead terminals should be placed close to the semiconductor element. It cannot be placed. Therefore, the bonding wire that electrically connects each electrode of the semiconductor element and the external lead terminal becomes long, and as a result, the bonding wire is used when the semiconductor element, the die pad and a part of the external lead terminal are covered with the mold resin. When an external force is applied to the bonding wire, the bonding wire is easily deformed by a slight external force, and adjacent bonding wires come into contact with each other to cause an electrical short circuit.

Therefore, in order to solve the above-mentioned drawbacks, a high density is formed in a fan shape from an electrically insulating material such as an aluminum oxide sintered body or the like, on which a semiconductor element is mounted, and from the periphery of the mounting portion to the outer peripheral portion. And a plurality of external lead terminals whose inner ends are arranged at substantially the same intervals as the intervals of the metallized wiring layers in the outer peripheral portion of the insulating substrate and whose inner ends are frame-shaped at the outer ends. A lead frame integrally connected by a connecting band is prepared, and the inner end of the external lead terminal is joined to the metallized wiring layer of the insulating substrate through a brazing material such as silver solder, solder or gold-tin solder. After that, the semiconductor element is mounted and fixed on the mounting portion of the insulating substrate, and each electrode of the semiconductor element is electrically connected to the metallized wiring layer through a bonding wire. It said insulating substrate, a semiconductor device has been proposed in which a part of the semiconductor element and the external lead terminals so as to cover a mold resin.

In such a semiconductor device, after the insulating substrate, the semiconductor element, and a part of the external lead terminals are covered with a molding resin, the external lead terminals are cut and separated from the frame-shaped connecting strip to electrically connect the external lead terminals. By making them independent and connecting each external lead terminal to the external electric circuit, the internal semiconductor element is electrically connected to the external electric circuit.

[0007]

However, in the semiconductor device described above, when the metallized wiring layer of the insulating substrate and the external lead terminal are joined via silver solder, for example, the aluminum oxide sintered body constituting the insulating substrate is formed. Has a large difference from the coefficient of thermal expansion of the metal mainly composed of copper that constitutes the lead frame, and the melting point of the silver solder that joins the metallized wiring layer of the insulating substrate and the external lead terminal is about Since the temperature is as high as 800 ° C. and the like, when the metallized wiring layer of the insulating substrate and the external lead terminal are joined via the silver brazing material, the difference in thermal expansion between the two becomes large, so that the metallized wiring layer and the external lead terminal are large. Since the positions of the lead frame and the metallized wiring layer are misaligned, it is difficult to join them accurately, and a large thermal stress is generated between the lead frame and the metallized wiring layer. External lead terminals or broken by the stress, will be peeled off from the metallized wiring layer, exactly the semiconductor element to the outside, to induce disadvantage and surely not be electrically connected.

Further, when the metallized wiring layer of the insulating base and the external lead terminal are joined via solder, the melting point of the solder is as low as 183 ° C., so that the insulating base, the semiconductor element and a part of the external lead terminal are When coating with mold resin,
Heat for thermosetting the molding resin (usually about 200 ℃)
Is applied, the solder is melted by the heat and the metallized wiring layer and the external lead terminal are disjoined or misaligned, and the internal semiconductor element is also accurately and surely electrically connected to the external electric circuit. Induced the drawback of not being able to.

Further, when the metallized wiring layer of the insulating substrate and the external lead terminal are joined via gold-tin solder,
The gold-tin brazing material has a hard and brittle property, and therefore when the semiconductor element is bonded and fixed to the insulating substrate, or when the electrode of the semiconductor element and the metallized wiring layer are electrically connected via a bonding wire, Alternatively, when an unnecessary external force is applied to the external lead terminal when the insulating substrate, the semiconductor element, and a part of the external lead terminal are covered with the mold resin, the external force causes cracks in the gold-tin brazing material, and the external lead The terminal was peeled off together with the brazing material from the metallized wiring layer, which caused a defect that the internal semiconductor element could not be accurately and surely electrically connected to the external electric circuit.

[0010]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional drawbacks, and an object thereof is to provide a semiconductor device capable of electrically connecting an internal semiconductor element to an external electric circuit accurately and surely. To provide.

[0011]

According to the present invention, there is provided an insulating base having a mounting portion on which a semiconductor element is mounted in the central portion of an upper surface and a metallized wiring layer extending from the periphery of the mounting portion to an outer peripheral portion, and mounting of the insulating base. A semiconductor element mounted on the metallization part and having electrodes connected to the metallized wiring layer, an external lead terminal joined to the metallized wiring layer via a brazing material, and one of the insulating substrate, the semiconductor element and the external lead terminal. In a semiconductor device comprising a mold resin for covering a portion, the brazing material joining the external lead terminal to the metallized wiring layer is a gold-tin-lead-silver alloy or a gold-tin-
It is characterized by being made of a lead-palladium alloy.

According to the present invention, the brazing material is gold 1.0 to 3
It is characterized by comprising 0.0% by weight, 3.0 to 40.0% by weight of tin, 33.0 to 93.0% by weight of lead, and 1.0 to 15.0% by weight of silver.

Further, in the present invention, the brazing material is gold 1.0 to 3
It is characterized by comprising 0.0% by weight, tin 3.0 to 40.0% by weight, lead 33.0 to 93.0% by weight, and palladium 1.0 to 15.0% by weight.

Still further, according to the present invention, an insulating base having a mounting portion on which a semiconductor element is mounted in the central portion of the upper surface and a metallized wiring layer extending from the periphery of the mounting portion to the outer peripheral portion, and the mounting portion of the insulating base are mounted. A semiconductor element whose electrodes are connected to the metallized wiring layer, and external lead terminals which are joined to the metallized wiring layer via a brazing material,
A semiconductor device comprising an insulating substrate, a semiconductor element and a molding resin that covers a part of an external lead terminal,
The metallized wiring layer of the insulating substrate and the external lead terminal are joined by the following steps (1) to (3). (1) Step of depositing a plated metal layer made of gold on the surface of the metallized wiring layer of the insulating substrate (2) A plated metal layer made of silver or palladium and a plated metal layer made of tin-lead alloy on the surface of the external lead terminal And (3) bringing the metallized wiring layer of the insulating substrate into contact with the external lead terminals and a part of the plated metal layer made of gold deposited on the metallized wiring layer and the external lead terminals. Is heated to a temperature equal to or higher than a temperature at which a gold-tin-lead alloy is formed by a part of the plated metal layer made of a tin-lead alloy deposited on the metal, and the gold is placed between the metallized wiring layer and the external lead terminal. A gold-tin-lead-silver alloy is formed by forming a tin-lead alloy and diffusing and melting a part of a plated metal layer made of silver or palladium deposited on the external lead terminal in the gold-tin-lead alloy. Or gold - tin - lead - form a palladium alloy, gold - tin - lead - silver alloy or gold - tin - lead - step through the palladium alloy to bond the metallized wiring layer and the external lead terminal

[0015]

According to the semiconductor device of the present invention, the metallized wiring layer of the insulating substrate and the external lead terminal are joined via the brazing material made of gold-tin-lead-silver alloy or gold-tin-lead-palladium alloy. The gold-tin-lead-silver alloy or gold-tin-lead-palladium alloy is excellent in toughness and has a melting point of about 250 ° C or higher, which is higher than the temperature at which the mold resin is heat-cured. After joining the external lead terminals to the wiring layer, the external lead terminals do not peel off together with the brazing material from the metallized wiring layer even if an unnecessary external force is applied to the external lead terminals. Also, the brazing material does not melt, and the external lead terminals can be securely and firmly joined to the metallized wiring layer.

Further, according to the manufacturing method of the present invention, the plated metal layer made of gold is deposited, and the metallized wiring layer, the plated metal layer made of silver or palladium, and the plated metal layer made of tin-lead alloy are sequentially deposited. A part of the plated metal layer made of gold and deposited on the metallized wiring layer and a part of the plated metal layer made of tin-lead deposited on the external lead terminal. Is heated to a temperature not lower than the temperature at which a gold-tin-lead alloy is formed to form a gold-tin-lead alloy between the metallized wiring layer and the external lead terminal, and A part of the plated metal layer made of silver or palladium deposited on the external lead terminals is diffused and fused to form a gold-tin-lead-silver alloy or a gold-tin-lead-palladium alloy,
Since the metallized wiring layer and the external lead terminal are bonded to each other through the gold-tin-lead-silver alloy or the gold-tin-lead-palladium alloy, the metallized wiring layer and the external lead terminal are connected to the gold-tin-lead alloy. It can be bonded at a low temperature of about 240 ° C, and as a result, when bonding the metallized wiring layer and the external lead terminal, the difference in the amount of thermal expansion between the two is extremely small and both are accurate and strong. The brazing material composed of a gold-tin-lead-silver alloy or a gold-tin-lead-palladium alloy, which has been once solidified, does not melt unless heated to about 250 ° C or higher.
It does not melt even with the heat of thermosetting the molding resin.

[0017]

The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of the semiconductor device of the present invention,
Reference numeral 1 is an insulating substrate, 2 is an external lead terminal, and 3 is a semiconductor element.

The insulating substrate 1 has a mounting portion 1a for mounting a semiconductor element in the center of the upper surface thereof.
The semiconductor element 3 is bonded and fixed to a by an adhesive such as resin, glass, or brazing material.

The insulating substrate 1 is made of an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body,
When it is made of an electrically insulating material such as a silicon carbide sintered body or a glass ceramics sintered body, for example, when it is made of an aluminum oxide sintered body, it is suitable as a raw material powder of aluminum oxide, silicon oxide, calcium oxide, magnesium oxide or the like. A binder and a solvent are added and mixed to form a slurry, and a ceramic green sheet is obtained by forming it into a sheet by adopting a conventionally known doctor blade method.After that, the ceramic green sheet is punched by a method such as a punching method. It is manufactured by punching into an appropriate shape, laminating a plurality of sheets as necessary, and finally firing the ceramic green sheet in a reducing atmosphere at a temperature of about 1600 ° C.

The insulating substrate 1 is formed with a large number of metallized wiring layers 4 spreading in a fan shape from the periphery of the upper surface mounting portion 1a to the outer peripheral portion, and the metallized wiring layer 4 is mounted on the periphery of the mounting portion 1a. The electrodes of the semiconductor element 3 are electrically connected via the bonding wires 5, and the external lead terminals 2 connected to the external electric circuit are joined to the outer peripheral portion of the insulating substrate 1 via the brazing material 6. .

The metallized wiring layer 4 is made of a refractory metal powder such as tungsten, molybdenum or manganese, and a metal paste obtained by adding and mixing an appropriate binder and a solvent to the refractory powder such as tungsten is mixed with the insulating substrate. The ceramic green sheet to be No. 1 is formed into a fan shape from the upper surface around the mounting portion 1a of the insulating substrate 1 to the upper surface of the outer peripheral portion of the insulating substrate 1 by applying a thick film method such as a well-known screen printing method to print and apply it in a predetermined pattern. It is formed so as to spread over.

Since the metallized wiring layer 4 is printed and applied by the screen printing method, it is possible to make the line width and the interval between the adjacent metallized wiring layers 4 as narrow as about 0.05 mm or less. , A large number of metallized wiring layers 4 are arranged in the vicinity of the semiconductor element 3
A short bonding wire 5 between the metallized wiring layer 4 and
It is possible to electrically connect with each other, and it is possible to effectively prevent an electrical short circuit between the adjacent bonding wires 5.

The external lead terminal 2 joined to the metallized wiring layer 4 via the brazing material 6 serves to connect the semiconductor element 3 housed therein to an external electric circuit, and the external lead terminal 2 is externally connected. By connecting to the wiring conductor of the electric circuit board, the semiconductor element 3 is electrically connected to the external electric circuit via the metallized wiring layer 4 and the external lead terminal 2.

The external lead terminals 2 are made of a metal such as a copper-based alloy containing copper as a main component or an iron-based alloy containing iron as a main component. For example, an ingot of a copper-based alloy is formed by a conventionally known rolling method. Then, it is formed into a plate shape having a predetermined thickness, and is subjected to etching processing or punching processing to have a predetermined shape.

When the external lead terminal 2 is formed of a metal containing copper as a main component, the metal containing copper as a main component is
The heat conductivity is excellent, and the heat generated when the semiconductor element 3 operates can be satisfactorily dissipated to the outside atmosphere through the lead terminals 2, so that the semiconductor element 3 can always be operated at a low temperature and stably operated. Therefore, the external lead terminals 3 are preferably formed of a metal containing copper as a main component.

The brazing material 6 which joins the external lead terminals 2 to the metallized wiring layer 4 is made of a gold-tin-lead-silver alloy or a gold-tin-lead-palladium alloy, and the external lead terminals 4 are metalized. It has the function of firmly bonding to the wiring layer.

Since the gold-tin-lead-silver alloy or the gold-tin-lead-palladium alloy forming the brazing material 6 has high toughness, even if an unnecessary external force is applied to the external lead terminal 2, the external lead will be exposed. Since the terminal 2 does not easily separate from the metallized wiring layer 4 together with the brazing material 6, and the melting points are about 250 ° C. or higher, the brazing material 6 is melted by the heat when the mold resin described later is thermally cured. Never,
The external lead terminal 2 can be securely and firmly bonded to the metallized wiring layer 4.

When the brazing material 6 is made of a gold-tin-lead-silver alloy, the gold contained in the brazing material 6 made of the gold-tin-lead-silver alloy is the metallized wiring layer 4 of the brazing material 6. When the content is less than 1.0% by weight, the wettability of the brazing material 6 becomes poor, and 3
If it exceeds 0.0% by weight, a large amount of brittle gold-tin intermetallic compound is formed in the brazing material 6 and the strength of the brazing material 6 becomes weak. Therefore, the brazing material 6 composed of the gold-tin-lead-silver alloy
It is preferable that the amount of gold contained in the alloy is 1.0 to 30.0% by weight.

Further, the tin contained in the brazing material 6 made of the gold-tin-lead-silver alloy acts together with lead to make the brazing temperature of the brazing material 6 about 240 ° C., and the content thereof is 3.0.
If it is less than 5% by weight, the brazing temperature of the brazing material 6 will be high, and if it exceeds 40.0% by weight, the wettability of the brazing material 6 with respect to the metallized wiring layer 4 tends to decrease. Therefore,
The tin contained in the brazing material 6 made of the gold-tin-lead-silver alloy is preferably in the range of 3.0 to 40.0% by weight.

The lead contained in the brazing material 6 made of the gold-tin-lead-silver alloy acts together with tin to make the brazing temperature of the brazing material 6 about 240 ° C., and the content thereof is 33.0.
If it is less than 10% by weight, the wettability of the brazing material 6 to the metallized wiring layer 4 tends to decrease, and if it exceeds 93.0% by weight, the brazing temperature of the brazing material 6 tends to be high. Therefore, the brazing material 6 made of the gold-tin-lead-silver alloy is used.
It is preferable that the lead contained in the alloy is in the range of 33.0 to 93.0% by weight.

Further, the silver contained in the brazing material 6 made of the gold-tin-lead-silver alloy acts to prevent the formation of a brittle gold-tin intermetallic compound in the brazing material 6, If the content is less than 1.0% by weight, it becomes impossible to effectively prevent the formation of brittle gold-tin intermetallic compounds in the brazing material 6, and if it exceeds 15.0% by weight, the brazing material 6 is brazed. The temperature will be high. Therefore, the silver contained in the brazing material 6 made of the gold-tin-lead-silver alloy is preferably in the range of 1.0 to 15.0% by weight.

When the brazing material 6 is made of a gold-tin-lead-palladium alloy, the gold contained in the brazing material 6 made of the gold-tin-lead-palladium alloy is the metallized wiring layer 4 of the brazing material 6. If the content is less than 1.0% by weight, the brazing material 6 has poor wettability, and if it exceeds 30.0% by weight, the brazing material 6 is fragile in gold-tin metal. A large amount of intercalation compound is formed, and the strength of the brazing material 6 becomes weak.

Therefore, the gold contained in the brazing material 6 made of the gold-tin-lead-palladium alloy is 1.0 to 30.0% by weight.
Is preferred.

The tin contained in the brazing material 6 made of the gold-tin-lead-palladium alloy has a function of keeping the brazing temperature of the brazing material 6 at about 240 ° C. together with lead, and the content thereof is 3.0 weight. If it is less than 4%, the brazing temperature of the brazing material 6 will be high, and if it exceeds 40.0% by weight, the wettability of the brazing material 6 with respect to the metallized wiring layer 4 tends to decrease.
Therefore, tin contained in the brazing material 6 made of the gold-tin-lead-palladium alloy is preferably in the range of 3.0 to 40.0% by weight.

The lead contained in the brazing material 6 made of the gold-tin-lead-palladium alloy has a function of keeping the brazing temperature of the brazing material 6 at about 240 ° C. together with tin, and its content is 33.0 weight. %, The metallized wiring layer 4 of the brazing material 6
The wettability of the product tends to decrease, and it is 93.0% by weight.
If it exceeds, the brazing temperature of the brazing material 6 tends to be high. Therefore, the lead contained in the brazing material 6 made of the gold-tin-lead-palladium alloy is preferably in the range of 33.0 to 93.0% by weight.

Further, the palladium contained in the brazing material 6 made of the gold-tin-palladium alloy acts to prevent the formation of a brittle gold-tin intermetallic compound in the brazing material 6, and its inclusion. If the amount is less than 1.0% by weight, it becomes impossible to effectively prevent the formation of brittle gold-tin intermetallic compounds in the brazing material 6, and if it exceeds 15.0% by weight, the brazing temperature of the brazing material 6 is increased. It will be expensive. Therefore, the money-
The amount of palladium contained in the brazing material 6 made of tin-lead-palladium alloy is preferably 1.0 to 15.0% by weight.

A part of the insulating substrate 1, the semiconductor element 3 and the external lead terminals 2 is covered with a mold resin 7 such as an epoxy resin, whereby the semiconductor element 3 is formed.
Will be hermetically sealed inside.

In order to cover a part of the insulating substrate, the semiconductor element and the external lead terminal with the molding resin 7, the insulating substrate 1 to which the semiconductor element 3 and the external lead terminal 2 are bonded is placed in a predetermined molding die. At the same time, a mold resin such as an epoxy resin is injected into the mold, and then the injected resin is thermally cured by applying a temperature of about 200 ° C. and a pressure of 100 kgf / mm 2.

Next, in the above-described semiconductor device, the external lead terminals 2 are formed on the metallized wiring layer 4 of the insulating substrate 1 with gold-tin-.
FIG. 2 (a) shows a method of joining through a brazing material 6 made of a lead-silver alloy or a gold-tin-lead-palladium alloy.
A description will be given based on (d).

First, as shown in FIG. 2A, an insulating substrate 1 having a metallized wiring layer 4 and external lead terminals 2 are prepared.

Next, as shown in FIG. 2B, a plated metal layer 8 made of gold is deposited on the outer surface of the metallized wiring layer 4 of the insulating substrate 1 to a thickness of 0.05 to 2.0 μm and the external lead terminals 2 are formed. A plated metal layer 9 made of silver or palladium with a thickness of 0.05 to 2.0 μm and a plated metal layer 10 made of a tin-lead alloy on the surface of 3.0 to 100.0 μm
It is sequentially deposited to a thickness of m.

Next, as shown in FIG. 2 (c), the inner ends of the external lead terminals 2 are placed on the metallized wiring layer 4 of the insulating substrate 1, and these are heated to a temperature of about 240.degree. A gold-tin-lead alloy is formed by a part of the plated metal layer 8 made of gold deposited on the layer 4 and a part of the plated metal layer 10 made of tin-lead alloy deposited on the external lead terminal 2. Between the metallized wiring layer 4 and the external lead terminal 2 by diffusing and melting a part of the plated metal layer 9 made of silver or palladium deposited on the external lead terminal 2 in the gold-tin-lead alloy. Gold-tin-lead-
A silver alloy or a gold-tin-lead-palladium alloy is formed, and finally the gold-tin-lead-silver alloy or gold-tin-lead-
2 (d) by cooling and solidifying the palladium alloy.
The external lead terminals 2 are formed on the metallized wiring layer 4 of the insulating substrate 1 as shown in FIG. 1 with gold-tin-lead-silver alloy or gold-tin-lead-.
It is joined via a brazing material 6 made of a palladium alloy.
In this case, since the metallized wiring layer 4 of the insulating base 1 and the external lead terminal 2 can be bonded at a low temperature of about 240 ° C., when the metallized wiring layer 4 and the external lead terminal 2 are bonded, The difference in the amount of thermal expansion from the external lead terminal 2 is extremely small, so that the positions of the metallized wiring layer 4 and the external lead terminal 2 are not displaced, and the metallized wiring layer 4 and the external lead terminal 2 are not separated from each other. No large thermal stress is generated. Further, the brazing material 6 made of the gold-tin-lead-silver alloy or the gold-tin-lead-palladium alloy once cooled and solidified does not remelt unless heated to a temperature of about 250 ° C. or more, and does not re-melt. 1,
The semiconductor element 3 and a part of the external lead terminal 2 are not melted by the heat when the mold resin 7 covers them. Therefore, according to the manufacturing method of the present invention, the external lead terminal 2 can be joined to the metallized wiring layer 4 of the insulating substrate 1 accurately and firmly.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-mentioned embodiments, the surface of the external lead terminal is A plated metal layer made of silver or palladium and a plated metal layer made of a tin-lead alloy were sequentially deposited on the entire surface, but the plated metal layer made of the tin-lead alloy was formed only on the brazed tip of the external lead terminal. It may be attached to.

[0044]

According to the semiconductor device of the present invention, the metallized wiring layer of the insulating substrate and the external lead terminals are made of gold-tin-lead-.
Bonded through a silver alloy or a gold-tin-lead-palladium alloy, the gold-tin-lead-silver alloy or gold-tin-lead-palladium alloy is excellent in toughness and has a melting point of about
Since the temperature is 250 ° C or higher, which is higher than the temperature for thermosetting the mold resin, even if an external force is applied to the external lead terminals after joining the external lead terminals to the metallized wiring layer, the external lead terminals will not be brazed. At the same time, it is not separated from the metallized wiring layer, and the brazing material is not melted when the mold resin is cured by heat, so that the external lead terminals can be securely and firmly bonded to the metallized wiring layer. Accurate semiconductor device to external electric circuit,
In addition, the electrical connection can be surely made.

Further, according to the manufacturing method of the present invention, the plated metal layer made of gold is deposited, and the metallized wiring layer, the plated metal layer made of silver or palladium, and the plated metal layer made of tin-lead alloy are sequentially deposited. A part of the plated metal layer made of gold that is deposited on the metallized wiring layer while being in contact with the external lead terminal that is made to contact with the external lead terminal, and a plated metal layer made of a tin-lead alloy that is deposited on the external lead terminal. And a temperature higher than a temperature at which a gold-tin-lead alloy is formed between the metallized wiring layer and the external lead terminal to form a gold-tin-lead alloy and the gold-tin-lead alloy. A part of the plated metal layer made of silver or palladium deposited on the external lead terminal is diffused and melted to form a gold-tin-lead-silver alloy or a gold-tin-lead-palladium alloy, and the gold-tin -Lead Since the metallized wiring layer and the external lead terminal are joined through the silver alloy or the gold-tin-lead-palladium alloy, the metallized wiring layer and the external lead terminal form a gold-tin-lead alloy at about 240 ° C. Can be bonded at low temperature.

Therefore, when the metallized wiring layer and the external lead terminal are joined together, the difference in the amount of thermal expansion between them can be made extremely small, and as a result, the positions of the metallized wiring layer and the external lead terminal are displaced. In addition, no large thermal stress is generated between them. Further, the brazing material composed of the once solidified gold-tin-lead-silver alloy or gold-tin-lead-palladium alloy does not remelt unless it is heated to about 250 ° C or more. It does not melt due to heat. Therefore, according to the manufacturing method of the present invention, the external lead terminal can be accurately and firmly joined to the metallized wiring layer of the insulating substrate,
As a result, the internal semiconductor element can be accurately and reliably electrically connected to the external electric circuit.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a semiconductor device of the present invention.

2A to 2B are enlarged cross-sectional views of a main part of each step for explaining the method for manufacturing the semiconductor device shown in FIG.

[Explanation of symbols]

 1 ... Insulating substrate 1a ... Mounting part 2 ... External lead terminal 3 ... Semiconductor element 4 ... Metallized wiring layer 5 ... Bonding wire 6 ... Brazing material 7 ... Mold resin 8 ... Gold plated metal layer 9 ... Silver or palladium plated metal layer 10 ... Tin-lead alloy plated metal layer

Claims (4)

[Claims] 1. An insulating base having a mounting portion on which a semiconductor element is mounted in a central portion of an upper surface and a metallized wiring layer extending from the periphery of the mounting portion to an outer peripheral portion, and an electrode mounted on the mounting portion of the insulating base and having electrodes as described above. From a semiconductor element connected to the metallized wiring layer, an external lead terminal joined to the metallized wiring layer via a brazing material, and a molding resin that covers the insulating substrate, the semiconductor element and a part of the external lead terminal. In the semiconductor device, the brazing material for joining the external lead terminal to the metallized wiring layer is made of a gold-tin-lead-silver alloy or a gold-tin-lead-palladium alloy. 2. The brazing material is gold 1.0 to 30.0% by weight, tin 3.
0 to 40.0% by weight, lead 33.0 to 93.0% by weight, silver 1.0 to
The semiconductor device according to claim 1, wherein the semiconductor device comprises 15.0% by weight. 3. The brazing material is gold 1.0 to 30.0% by weight, tin 3.
0 to 40.0% by weight, lead 33.0 to 93.0% by weight, palladium
A composition comprising 1.0 to 15.0% by weight.
The semiconductor device according to. 4. An insulating base having a mounting portion on which a semiconductor element is mounted at the center of the upper surface and a metallized wiring layer extending from the periphery of the mounting portion to the outer periphery, and an electrode mounted on the mounting portion of the insulating base and having electrodes as described above. From a semiconductor element connected to the metallized wiring layer, an external lead terminal joined to the metallized wiring layer via a brazing material, and a molding resin that covers the insulating substrate, the semiconductor element and a part of the external lead terminal. A method of manufacturing a semiconductor device, wherein the metallized wiring layer and the external lead terminal are joined by the following steps (1) to (3). (1) Step of depositing a plated metal layer made of gold on the surface of the metallized wiring layer of the insulating substrate (2) A plated metal layer made of silver or palladium and a plated metal layer made of tin-lead alloy on the surface of the external lead terminal And (3) bringing the metallized wiring layer of the insulating substrate into contact with the external lead terminals and a part of the plated metal layer made of gold deposited on the metallized wiring layer and the external lead terminals. Is heated to a temperature equal to or higher than a temperature at which a gold-tin-lead alloy is formed by a part of the plated metal layer made of a tin-lead alloy deposited on the metal, and the gold is placed between the metallized wiring layer and the external lead terminal. A gold-tin-lead-silver alloy is formed by forming a tin-lead alloy and diffusing and melting a part of a plated metal layer made of silver or palladium deposited on the external lead terminal in the gold-tin-lead alloy. Or gold - tin - lead - form a palladium alloy, gold - tin - lead - silver alloy or gold - tin - lead - step through the palladium alloy to bond the metallized wiring layer and the external lead terminal